# CVE-2020-37023: Koken CMS 0.22.24 - Arbitrary File Upload

> Authenticated attackers can upload malicious PHP files to Koken CMS, leading to arbitrary code execution on the server.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 30 Jan 2026
- **Updated:** 3 Feb 2026
- **Also known as:** GHSA-jfgg-fv6q-274f

## What is CVE-2020-37023?

CVE-2020-37023 is a high-severity vulnerability in Koken CMS, published on 30 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Koken CMS 0.22.24 contains a file upload vulnerability that allows authenticated attackers to bypass file extension restrictions by renaming malicious PHP files. Attackers can upload PHP files with system command execution capabilities by manipulating the file upload request through a web proxy and changing the file extension.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type)

## Which versions are affected by CVE-2020-37023?


## How do I fix CVE-2020-37023?

No fix has been published for CVE-2020-37023 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-37023 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-37023 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-37023 and fix it if it is affected.

What it is: CVE-2020-37023 is a high-severity vulnerability in Koken CMS, published on 30 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-37023 exists.

Affected product: Koken CMS. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2020-37023/ (Markdown: https://insights.sbomify.com/CVE-2020-37023/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-37023
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-37023
- OSV: https://osv.dev/vulnerability/CVE-2020-37023

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-37023/
Summaries are generated and may contain mistakes; the official description above is the record.